Conventionally, when a continuity test or a performance characteristics test of a test subject such as a semiconductor integrated circuit and a liquid crystal panel is performed, a probe unit that accommodates multiple contact probes has been used to obtain electrical connection between the test subject and a signal processing device that outputs test signals. For the probe unit, with the recent progression of high integration and miniaturization of semiconductor integrated circuits and liquid crystal panels, a technique applicable to highly integrated and miniaturized test subjects has been improved by narrowing pitches between contact probes.
As a continuity test or a performance characteristics test of a test subject such as a semiconductor integrated circuit and a liquid crystal panel there is four-terminal measurement. As this four-terminal measurement, a manufacturing method of a probe unit is disclosed (for example, refer to Patent Literature 1) that measures electric characteristics with a set of contact probes (probe group) held by a guide plate by bringing the end of each contact probe into contact with a contact target (subject of measurement).
The contact probe disclosed in Patent Literature 1 comes into contact respectively with leads at one end, and comes into contact with a contact target at the other end. The probe group is brought into contact with the contact target at the same time, and thereby performs four-terminal measurement. According to Patent Literature 1, by differing diameters of the respective contact probes in a direction perpendicular to a direction of insertion to the guide plate, the contact probes are efficiently arranged.